This survey has been running on S-Scale.io for the past week.
https://www.surveymonkey.com/r/BDDF6BD
I'm not sure what will become of the data. Granted, it's from the Scale perspective and the first one from this author, but it may be worth a look for you Flyer and HiRail folks. After all, the main difference is wheels and couplers...
Rusty